CoO nanoparticle decorated N-doped carbon nanotubes: a high-efficiency catalyst for nitrate reduction to ammonia

Abstract

Ambient electrochemical NO3− reduction is emerging as an appealing approach toward eliminating NO3− contaminants and generating NH3 simultaneously, but its efficiency is challenged by a lack of active and selective electrocatalysts. In this work, we report CoO nanoparticle decorated N-doped carbon nanotubes as an efficient catalyst for highly selective hydrogenation of NO3− to NH3. In 0.1 M NaOH electrolyte with 0.1 M NO3−, this catalyst is capable of achieving a large NH3 yield of up to 9041.6 ± 370.7 μg h−1 cm−2 and a high faradaic efficiency of 93.8 ± 1.5%, with excellent durability. Theoretical calculations reveal the catalytic mechanisms.